Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.8 (polynucleotide phosphorylase)
 723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Homopolymers of etheno CMP have been prepared by the action of polyribonucleotide phosphorylase upon etheno CDP. At alkaline pH the optical properties are consistent with a structure consisting of partially helical single-stranded chains whose helical regions are stabilized by base stacking. At acid pH the degree of helicity increases markedly. The degree of cooperativity displayed by the helix leads to coil transition induced by pH or temperature is less than for the case of polyribocytidylic acid. In the presence of acridine orange the alkaline form develops a strong extrinsic CD spectrum.
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PMID:Physical properties of poly (3,N4-ethenocytidylic acid). 62 74

GroEL, as conventionally purified, can be incubated with nucleotides to produce high molecular weight material with an absorption maximum at 260 nm. This material is most clearly demonstrated when samples are subjected to gel filtration under conditions where GroEL is monomeric. There is a time-dependent increase in the high molecular weight material that occurs on incubation with ADP or, more slowly, with ATP. This material is generated during incubation, and none is present in the initial samples. Experiments with nucleases, proteases, radiolabeled nucleotides, and chemical cleavage reagents demonstrate that the high molecular weight material is polyadenylic acid whose formation is inhibited by phosphate. These results are consistent with the GroEL samples containing polynucleotide phosphorylase activity. Nondenaturing gels stained with acridine orange, after incubation in ADP, reveal that the activity producing the poly(A) coelectrophoreses with authentic polynucleotide phosphorylase. Conditions that remove the tryptophan-like fluorescence from preparations of GroEL also remove the PNPase activity. Thus, this activity is not associated with GroEL itself. The results are consistent with reports that GroEL can associate with RNase E and with other studies showing that RNase E and PNPase can form complexes. Thus, the present experiments support suggestions that GroEL can participate in multiprotein complexes that are involved in mRNA processing and degradation.
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PMID:Nucleotides reveal polynucleotide phosphorylase activity from conventionally purified GroEL. 881 Feb 58